When looking for places to play, I always had a really hard time getting behind places based on movies, tv shows, or major book series like Lord of the Rings, because they never felt as open ended to me. I feel like the major stories there have already been told and exhausted (generally speaking), so I'm less inclined to even consider those options. *
As a result, I was dragged to an oWoD MUD (that really only did rp and ignored the MUD aspects after a while. It was silly) by a good friend from where I'd been wading through RP in Yahoo! chatrooms and IRC stuff. Never thought I'd stick around, but the appeal of creating an entirely unique character, in a setting that is open ended enough that you feel like you /can/ do anything if you wanted to, got me hooked on WoD. I'm also a sucker for urban fantasy (and post apocalypse, but that's slightly less related), so that really helps. Playing the monster is a big draw for me, too. I don't tend to read too in depth the stories provided in the books, because of what I mentioned earlier with the stories already being told. Other than maybe a quick skin for theme/feel, but really I rely on wikis from the actual game for most of that.
A big factor for me, too, is that my circle of friends (albeit very small these days), play WoD, so I've kind of kept to the genre because of that. The option of splats to play, often on the same game, is a big draw for me as well. Always did like the cross-sphere rp.
I guess the TL:DR version of that ramble would be: **I feel like I can be more creative with my characters in a WoD setting. **
*With the exception of one Star Wars game from a while back - Star Wars: Age of Strife
/rambling